Cervical Dystonia

Synonyms of Cervical Dystonia

focal dystoniaidiopathic cervical dystonia

spasmodic torticollis

spasmodic wryneck

torticollis

General Discussion

Cervical dystonia, also known as spasmodic torticollis, is a rare neurological disorder characterized by involuntary muscle contractions in the neck that cause abnormal movements and postures of the neck and head. In some cases, these abnormal contractions may be sustained or continuous; in others, they may be present as spasms that can resemble tremor. The severity of cervical dystonia can vary, but the disorder can cause significant pain and discomfort as well as difficulty due to the abnormal postures. Cervical dystonia typically begins in middle age, and rarely begins in adolescence and young adulthood. The cause of cervical dystonia is unknown, although a genetic susceptibility is thought to underlie some cases. If cervical dystonia begins in infancy or early childhood, secondary causes should be investigated.

Cervical dystonia is the most common form of focal dystonia that presents in an office setting. Dystonia is generally characterized by involuntary muscle contractions that force the body into abnormal, sometimes painful, movements and positions (postures). Cervical dystonia is a form of dystonia that involves the neck area. Symptoms may vary among affected individuals, including the age at onset, intensity, presence of pain, and degree of disability.

Signs & Symptoms

The symptoms of cervical dystonia may begin slowly and can involve any of the muscles of the neck. The head posture in cervical dystonia can vary. The most common abnormal posture associated with cervical dystonia is the twisting of the chin toward a shoulder so that the head rotates sideways (torticollis). Other abnormal postures associated with cervical dystonia including anterocollis, in which the head tips forward; retrocollis, in which the head is tilted backward; or laterocollis, in which the head tilts toward one side. There can also be shifting of the head on the shoulders in a forward (anterior sagittal shift) or backward (posterior sagittal shift) direction. Often cervical dystonia is complex and combines several angles of head movement. In some people with primary CD, there may also be a postural tremor of the hands. Symptoms of cervical dystonia vary over the course of the disorder. Although it was once thought that after five years of symptoms, cervical dystonia will be stable, studies of the natural history of CD are lacking. Symptoms may temporarily worsen with stress or excitement, and often can have a posture or activity that worsens the symptoms. Symptoms may improve with the performance of sensory tricks, such as touching the cheek or the back of the head. A small percentage of individuals experience a spontaneous recovery (remission) after symptom onset. This remission is often temporary, lasting days to years, with recurrence of symptoms. It is likely that less than 1 percent of affected individuals have permanent remissions.

There can be secondary problems arising from cervical dystonia that include cervical spine arthritis, compression of nerve roots, and sometimes narrowing of the spinal cord in the neck (cervical stenosis). Pain related directly to cervical dystonia typically is on the same side as the head turn and is felt as muscular pain in the area of the overactive muscles. Pain can potentially become severe and disabling.

Causes

Cervical dystonia is sometimes classified as primary (no identifiable underlying cause) or secondary (occurring as consequence of another disorder or condition). In most cases, the cause of primary cervical dystonia is unknown (idiopathic) and there may not be a family history (sporadic). In approximately 10 to 25 percent of cases, there may be one or more family members with cervical dystonia suggesting that these individuals may have a genetic susceptibility to developing the disorder. A person who is genetically predisposed to a disorder carries a gene (or genes) for the disease, but it may not be expressed unless it is triggered or “activated” either by other genetic modifiers or environmental factors (complex genetics).

In some cases in which multiple family members have been affected, early-onset generalized dystonia may also be present. This form of dystonia may be associated with mutations in the DYT1 gene. The role, if any, that this gene plays in the development of sporadic cervical dystonia is likely minimal, and other gene mutations are likely to be involved. The DYT6 gene has been identified, and often presents with familial cervical dystonia associated with dystonic dysarthria, although the full role of this gene is not yet fully understood. Additional research is necessary to determine what genetic factors are associated with the cervical dystonia.

Several theories exists that attempt to explain the underlying mechanism of primary or idiopathic cervical dystonia including abnormal functioning of the basal ganglia or imbalances in neurotransmitters. Although the underlying mechanisms and causes of cervical dystonia are not well understood, research is ongoing to determine the specific roles that genetic, environmental and other factors ultimately play in the development of the disorder.

Some cases of cervical dystonia may have an identifiable cause (secondary cervical dystonia). In these cases, cervical dystonia may develop due to the use of certain drugs such as anti-psychotics, exposure to certain toxins such as heavy metals, neurodegenerative disease, or as part of a larger neurological disorder (often with abnormal functioning of the basal ganglia). In addition, there can be conditions such as atlanto-axial subluxation of the cervical spine that resembles dystonia, but is a structural disorder.

Trauma, either to the neck or the nervous system, as a cause of cervical dystonia, is controversial. Often, the cervical dystonia following trauma is fixed and painful. Whether there are psychiatric components to post-traumatic cervical dystonia has been discussed. The link between trauma and cervical dystonia, if it exists, is not fully understood.

Affected Populations

Cervical dystonia affects women approximately twice as often as men. It is the most common form of focal dystonia in an office setting. Cervical dystonia may affect individuals of any age, but typically develops in people between 40 and 60 years of age. Cervical dystonia affects people of all ethnic backgrounds. The exact incidence or prevalence of cervical dystonia in the general population is unknown.

Related Disorders

There a variety of conditions that can cause symptoms similar to cervical dystonia including stiff neck, wryneck, arthritis and various orthopedic or congenital problems that are localized to the neck. These are considered to be “pseudodystonia” and arise largely from structural abnormalities.

Dystonia is a group of complex movement disorders that varies in their symptoms, causes, progression, and treatments. This group of neurological conditions is generally characterized by involuntary muscle contractions that force a certain part(s) of the body into abnormal, sometimes painful, movements and positions (postures). Dystonia is not a single disease, but rather a diverse group of conditions with a variety of symptoms. There are many different causes for dystonia. Genetic as well as non-genetic factors contribute to all forms of dystonia. The most characteristic finding associated with dystonia is twisting, repetitive, writhing movements that affect a certain part(s) of the body such as the neck, or an arm or leg, or the face. (For more information on this disorder, choose “Dystonia” as your search term in the Rare Disease Database.)

Diagnosis

A diagnosis of cervical dystonia is based upon clinical examination, a detailed patient history, and knowledge of the disorder. No specific laboratory or imaging test confirms a diagnosis of cervical dystonia. A variety of specialized tests including blood tests, electromyography and specialized imaging techniques such as magnetic resonance imaging may be used to rule out underlying conditions if indicated.

Standard Therapies

Treatment

Not every treatment option for cervical dystonia is successful for all affected individuals. Therefore, no single strategy is appropriate for every case. Most therapies are symptomatic and are intended to relieve spasms, pain and disturbed postures or functions. Identifying the treatment regimen that is most effective in individual cases may require patience and perseverance on the part of the patient and physician.

There are essentially three treatment options: botulinum toxin injections, oral medications, and, in some cases, surgery. These treatments may be used alone or in combination. In addition, physical and speech therapy may provide a helpful complement to medical treatment. In some cases, a soft cervical collar has proven beneficial.

Botulinum toxin injections are the primary and most effective form of treatment for cervical dystonia. Botulinum toxin is a neurotoxin that is injected into muscles in very small doses. After injection into a muscle, the action of botulinum toxin is to interrupt nerve message to the muscle, and gives rise to weakness of that muscle. The effect of botulinum toxin on the muscle begins approximately 2-3 days following injection, peaks at around 4 weeks, and provides relief for approximately 3-6 months. When the effect of botulinum toxin wears off, the symptoms of cervical dystonia recur. In order for botulinum toxin injections to be successful, it is critical that the injecting physician be well-versed in cervical dystonia, the functional anatomy of the neck muscles, and the type and doses of botulinum toxin to use.

There are now four brands of Botulinum toxin that have been approved by the Food and Drug Administration (FDA) for the treatment of individuals with cervical dystonia. There are three brands of botulinum toxin serotype A, including unobotulinumtoxinA (BOTOX, Allergan Inc.) abobotulinumtoxinA (Dysport, Tercica Inc) and rimabotulinumtoxinA (Xeomin, Merz Pharmaceuticals). There is one formulation of botulinum toxin type B called rimabotulinumtoxinB (Myobloc, Solstice). These brands are not interchangeable, and each should be administered as a unique drug. The FDA has a “black box” warning concerning the use of any of these toxins.

There are no oral medications that are FDA approved for use in dystonia. Among the oral medications used, dopaminergic agents (levodopa), anticholinergic agents (benztropine, trihexyphenidyl), baclofen and clonazepam are the most frequently used. These drugs are usually most effective in children with generalized dystonia. In adults, side effects are often dose limiting.

Surgery is considered a last resort. Current studies suggest that deep brain stimulation surgery (DBS) is effective for cervical dystonia, although not as well investigated as DBS for generalized dystonia. DBS involves the surgical placement of very thin electrodes into both sides of the brain in an area called the globus pallidus. The electrodes are connected to stimulators which send small electrical pulses to the brain. After the DBS is placed, the stimulators are programmed for the optimal outcome.

Selective peripheral denervation in which the nerves to the dystonic muscles are severed has been reported to benefit patients with cervical dystonia who fail other therapies. However, this surgery requires a surgeon who is extensively trained both in the evaluation CD and in the surgical procedure. Side effects from the surgery are not uncommon and following surgery, there is a long period of rehabilitation.

Investigational Therapies

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. Government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222

TTY: (866) 411-1010

Email: prpl@cc.nih.gov

For information about clinical trials sponsored by private sources, contact:

NORD's Rare Disease Database provides brief introductions for patients and their families to more than 1,200 rare diseases. This is not a comprehensive database since there are nearly 7,000 diseases considered rare in the U.S. We add new topics as we are able to do so, with the help of rare disease medical experts.

If you are seeking information about a rare disease that is not in this database, we would suggest contacting the Genetic and Rare Diseases Information Center (GARD) at the National Institutes of Health. NIH has the most complete database of rare diseases in the U.S.

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